1.7.0 is working great for me on my 4x RX 560 (XfX 2GB) rig mining CNv8. I'm getting 460-490H/s per card with intensity set to 25.0 and using MSI AB 4.5.0 to set core at 1200, mem at 1900 and 100% PL (running an Anorak powersave BIOS). I really like the restart miner if hashrate drops below a certain value function as it seems that one or both of the middle two cards on this rig will drop in hashrate by about 150H/s every so often.
All in all, I'm happy to pay the dev fee vs. running xmr-stak compiled to have no devfee, as the latter barely did better than 400H/s per card and it had stability problems when it did run. Unfortunately, I am running at a razor thin margin of profitability vs. power cost right now, and it is only because the weather turned cooler recently that I am keeping this rig running at all (everything else was turned off and/or sold earlier this year).
Sounds like a power issue. My rig can exhibit problems like that if I re-apply ODT settings and/or restart the miner several times. It seems like some "power degradation" thingy happens when the cards/system are cycled too many times. The only remedy is to completely power off the rig including the psu for at least 5 minutes then power back on.